Mold adapted for use in vulcanizing rubber articles



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W. F. CLARK.

MOLD ADAPTED FOR USE IN VULCANIZING RU B APPLICATION FILED JAN. 12, 1920.

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W. F. CLARK MOLD ADAPTED FOR USE IN VULCANIZING RUBBER ARTICLES.

APPLICATION FILED JAN. 17, I920.

Patented July 11, 1922.

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WARREN IE. CLARK, OF CLEVELAND, OHIO, ASSIGNOBI; BY MESNE ASSIGNMENTS, T0

AUTOMATIC ELECTRIC HEATER COMPANY, OF WARREN, PENNSYLVANIA, A. COR- ronezrron or DELAWARE.

mom) 'ADAPTED FOR USE IN VULCANIZING RUBBER. An'rIoLns.

Specification of Letters Patent.

Patented July ii, 1922.

Application filed January 17, 1920. Serial No. 352,012.

T0 all whom itimay concern:

Be it known that I, WARREN F. CLARK, a citizen of the United States, residing at Cleveland, in the county of Cuyahoga and State of Ohio, have invented a certain new and useful Improvement in Molds Adapted for Use in Vulcanizing Rubber Articles, of which the following is a full, clear, and exact description.

The present invention relates to a mold intended for use in the vulcanizing of rubber articles.

The present embodiment of the invention is shown and described with respect to a mold for vulcanizing rubber tires, although the invention is not limited in this respect.

The object of the invention is to provide a mold which may be heated by the heat from an electric resistance coil which is so associated with the mold that its heat 'will pass directly trom the coil to the wall of ,the mold and thence to the article to be Vulcan ized. u

A further object is to provide means for controlling the functioning of the electric resistance coil which is so positioned with v respect to the coil and the article being vulcanized as to be very sensitive and responsive to changes in temperature condition.

A further object is toprovide a mold so constructed that the resistance coil is associated with. the mold in such a manner that y it is readily accessible and at the same time j is protected against injury and contact with water during the quenching or cooling operation after the vulcanizing action is completed and prior to the opening of the mold.

Other objects will appear more at large as the description proceeds.

Reference should be had to the accompanying drawings forming a part of this specification in which Fig. 1 is an elevation of a mold embodying my invention; Fig. 2 is a transverse sectional-elevation of a portion of a mold; Fig. 3 is aside elevation of a mold; Fig. 4 is an elevation of a controlling element; Fig. 5 is a section of a tire mold showing a modified construction; Fig. 6 is a section of a tire mold showing an arrangement for remote placement of the circuit controlling devices and temperature recording devices; Fig. 7 is an electrical diagram;

sired form of casingand tread portion there-- for, and all of these forms no part of the present lnvention.

The two parts of the mold may be held to-' gether in any suitable manner, by clamps or otherwise art.

Each part of the 'mold is formed with an annular cavity which extends around the mold section and is indicated at 4; in the drawings. The outer portion of each half of the mold is provided with a ledge 5 and adjacent the inner portion of each mold there is a ledge 6, each of these ledges being annular and are adapted 0t receive a cover 7 which cover is secured to the mold section in any desired manner as by means of stud bolts 8. The upper surface of the ledges 5 and 6 and the cooperating surface of the as at present is common in the cover 7 are provided with slight recesses adapted to receive packing material 9 so that when the cover 7 is bolted in position, the packing effects a sealed tight joint which prevents the entrance of water and the cover generally provides a protection for the electric resistance coil.

Within the cavity 4 there is an electric re sistance coil 10 which is wound so as to lie against the inner wall of the cavity 4 and in substantially direct contact with the wall. This coil is covered by a layer of nonheat conducting material which isindicated at 11. This material is in its original condition plastic when applied to the coil so that the material 11 is molded in place serving to hold the coil in its proper position and at the open market under the name Alundum, the heating coil and the article being vuland another composition which has been canized, hence, the tube 13 is in direct path 'found" suitable for-the purpose is that which of the heat passing from the coil to the is disclosed in U. S. Patent No. 1,393,316, rubber article and rise in temperature is granted October 11, 1921. quickly imparted to the tube 13, which As will be apparent, the heat generated by causes expansion of the Bourdon tube and the passage of current through the resistance so effects separation of the contacts 20 and coil is applied directly to the inner walls of 21 when the expansion of the Bourdon tube the mold and these walls in the present conhas reached the point for which adjustment struction may be made much thinner than has been made.

the walls of molds are usually made, and The action of the heat on the tube- 13 is hence less heat is absorbed in the Walls of the therefore a direct action and the volatile molds themselves than molds of usual conmaterial in the tube 13 is effected by the struction wherein heat is applied to the outheat coming from the heating coil before.

side of the mold and must penetrate from the heat the outside through the mass of iron of mold. which the molds are usually formed. It will be apparent that a mold of the The electric resistance coil is in an eX- character described opens u a a wide range ceedingly good position to directly apply of usefulness, inasmuch as t e temperature the heat and hence practically the entire to which the article being vulcanized is sub heating effect of the coils is applied to heatjected, may be very accurately controlled by ing the rubber article which is, to be vulthe controlling device and it is therefore canized. only a question of controlling the time of Furthermore, as is well known the'tread application of heat to insure a thorough portion of a tire is thicker than the sides andflproper vulcanization of the article conhence by the present invention more heat tained in the mold. may be applied to the tread and hence the ,In Fig. 5 there is shown a mold construccure may be controlled. 'tion embodying the heating coil associated Each section of the mold is provided with therewith, in which a tube 30 containing a a recess such as indicated at 12. This recess readily volatilizable fluid is inserted through is adapted to receive such a device as illusone of the covers 7, being mounted therein trated in Fig. 4. This device comprises a so that it extends into the space between the tube 13 adapted to contain a readily volacoil and the cover. This tube 30 is therefore tilizable substance such as ether. One end more remote from the article being 'vulof the tube is closed and the open end is canized than is the case in the construction secured to, the neck 14 of a covering 15 shown in Fig. 2, but under certain circumwithin which is housed a Bourdon tube 16. stances it is desirable to control the func- The Bourdon tube at its free end is provided tioning of the electric coil by a temperature with a pin 17 which lies bet-ween contact condition which is more remote from the carriers 18 and 19. These contact carriers article to be vulcanized, so as to efi'ect funcare provided with contacts which are intioning of the electric coil under lower temdicated at 20 and 21. One of the contact perature conditions than would be the case carriers, for instance, the contact carrier where the, tube containing'the volatilizable 18, 1s resilient and the pin 17 is positioned substance is inserted within a wall of the so that it may engage with the contact mold itself as is-the case in Fig. 2. carrier 18, when the Bourdon tube is ex- It will be understood'that' the tube 30 is panded and so break the contact. connected to a suitable pressure responsive Provision is made for adjusting the condevice which is associated with an electric tact carriers 18 and 19 with respect to the circuit make and break device, such as shown pin 17 so that the relative position may be in Fig. 4:. changed so as to cause engagement between Fig. 8 embodiesa'mold construction wherecontact carrier 18 and pin 17 at any prein the inner part of the mold is provided determlned pressure condition which .preswith an opening, as indicated at 50, through sure is'a direct function of the temperature. which there may extend a tubular member The contacts 20 and 21 are normally in 51 containing a readily volatilizable subcontact and are separated by the expansive stance. The tube being connected with a passes to the article within the action of the Bourdon tube. The contacts pressure control device as previously exare in suitable connection with the circuit plained. This construction permits the conwhich includes one of the electric coils so trol of the heating coils to be overned by that the functioning of the electric coil is temperatureconditions within 51c vulcanizcontrolled by the functioning of the Bouring cavity of the mold.

don tube. The tube 13 of the control ele- In Fig. "6 there is shown an arrangement ment is inserted in the recess 12 to which whereby the tubes such as tubes 13 are conreference has before been made and as will nected b means of what is known as capilbe noted therefore, the tube 13 lies'between lary tubing, which is usually copper tubing of small internal diameter, such as indicated at 32, with a controlling device such as indicated at 33 and with a temperature indicating and controlling device such as indicated at 34. The devices which have just been referred to may be mounted upon a panel or board 35 which is situated at a point more or less remote from the position of the mold itself and the panel may be located at some central oint where other panels connected with ot er molds are assembled, so that the condition and function ing of a plurality of molds may conveniently be kept track of by a single attendant.

By the foregoing it is not intended to ,mean that the panel 35 need necessarily be located at a point remote from the mold, as it may be located very near to the mold and the tubes 32 which are connected with the tubes 13, which are adapted to be in serted in the mold cavities, may be detached' from the mold and removed after the vulcanizing operation is completed. The panel 35 may therefore carry all the necessary controlling and recording devices which are desirable or essential for securing the con,- trolled functioning ofthe heating coil in the mold. g

The panel 35 has indicated at 36, in a conventional manner, a relay with which the contacts 18 and 21 of the pressure control device (see Fig. 4) are connected.

The electrical connections are indicated in the diagram shown in -Fig. 7 wherein 38 and 39 indicate the two wires of a power circuit from which electricity is secured for operating the heating coil or coils 10. A suitable relay device may consist of a coil 40 which is electrically connected with one of the contacts of thepressure control device, such for instance as the contact 20 and the other end of the coil may be connected vwith a conductor which connects with one of the conductors 38-39. l Vithin the coil is an iron core 41 which at its lower end has a cross member 42. Located above the cross member 42 are contacts 43 and 44. Normally the contact-member 42 is depressed and out of engagement with the contacts with one of the conductors 38 or 39, as illustrated in the diagram.

When the. contacts 21 and 20 are in engagement, the coil40 is energized and the contacts 43 and 44 are connected. When the .contaots 20-21 are separated, the coil 40 is not energized and consequently the contacts 43-44 are not connected.

" The relay is used because the current required by the coil 10 to effect the desired heating result is a heavy current and it can- 7 not be handled by such contacts as the contacts 20 and 21 of the pressure controlling device. The diagrammatic representation and description of the relay as given is merely to indicate the manner in which a relay would be used in the present connection and out injury of the contacts 20 and 21 of'the pressure controlling device, the electric circuit including the heating coil may be directly controlled by the make and break between the contacts 20 and 21.

Having described my invention, I claim- 1. The combination with a mold for'use in vulcanizing rubber articles, said mold having a wall of approximately uniform thickness, one surface of which is adapted to cooperate with the article to be molded, an electric heating coil cooperating with the other surface of the wall and substantially coextensive with the first mentioned surface of the-wall. v i

2. The combination with a 'mold for use in vulcanizing rubber articles, said mold having a wall, a surface of which is adapted to cooperate with the article to be vulcanized, said mold being provided with a recessed portion, of an electric heating coil occupying said recessed portion and engaging with an outer surface of said wall and substantially coextensive with the inner or molding surface.

3. The combination with a mold for use in vulcanizing rubber articles, said mold having a wall, the inner surface of which is adapted to cooperate with an article to be molded, said moldhaving a recessed portion, an electric heating coil in said recess and cooperating with the outer surface of said wall and substantially coextensivewith the' inner or molding surface and a cover member secured to the mold and enclosing the coil in the recessed portion.

4. In combination, a mold adapted for use in vulcanizing rubber articles, said mold having a wall, the inner surface of which is adapted to cooperate with the article to be vulcanized, an electric heating coil cooperating/with the outer surface of said wall and substantially coextensive with the V inner surface thereof, a recess in the said wall between the inner and outer surface thereof adapted to receive a temperature responsive device.

5. In combination, a mold adapted for use mately uniform thickness, the inner surfaces 130 a of which walls form the mold cavity for the article to be vulcanized, an electric heating coil cooperating with the outer surface of each such wall and substantially coextensive with the inner surface of each wall.

6. In combination, a mold adaptedfor use the outer surface of each wall, said heating coil substantially covering said surface, a cover overlying each heating coil and secured to a mold SGCtlOIl, an opening formed in said cover, a tube containing a volatilizable substance extending through said opening and in vulcanizing rubber articles, said moldiecured therein.

comprising a plurality of cooperating sections, each of said sections being formed with a wall, the inner surface of which forms a part of the mold cavity, a heating coil cooperating with the outer surface of each wall, said heating coil substantially covering said surface, each of said walls having a recess lving bet-ween the outer and inner surface o f the wall adapted to receive a temperature responsive device.

7. In combination, a tire mold composed of two cooperating sections, each of said sections having a wall, the inner surface of which forms part of the mold cavity, an electric heating coil cooperating with the outer Surface of said wall and substantially covering the same, a cover member secured to said mold and enclosing the heating coil.

8. In combination, a mold adapted for use in vulcanizing rubber articles, said mold having a wall, the inner surface of which forms part of the mold cavity, a heating coil cooperating with the outer surface of said wall substantially covering the same, a recess in said wall lying between the inner and outer surface thereof, a temperature responsive device inserted in said recess and a connection between the coil and the temperature responsive device whereby the functioning of the coil is controlled by said temperature responsive device.

9. In combination, a mold adapted for use in vulcanizing rubber articles, said mold comprising a plurality of sections, each of said sections being formed with a wall the inner surface of which forms a part of the mold cavity, a heating coil cooperating with the outer surface of each Wall, said heating coil substantially covering said surface, a cover overlying each heating coil and secured to a mold section.

10. In combination, a mold adapted for use in vulcanizing rubber articles, said mold comprising a plurality of sections, each of said sections being formed with a wall the inner surface of which forms a part of the mold cavity, a heating coil cooperating with 11. In combination, a mold adapted for use in vulcanizing rubber articles, said mold comprising a plurality of sections, each of said sections being formed with a wall the inner surface of" which forms a part of the mold cavity, a heating coil cooperating with the outer surface of each wall, said heating coil substantially covering said surface, a cover overyling each heating coil and secured to a mold section, said cover having an opening, a tube adapted to contain a volatilizable substance extending through said opening and into the space between the electric coil and the cover.

12. In combination, a mold adapted for use in vulcanizing rubber articles, said mold comprising a plurality of sections, each of said sections being formed with a wall the inner surface of which forms a part of the mold cavity, a heating coil cooperating with the outer surface of each wall, said heating coil substantially covering said surface, a cover overlying each heating coil and secured to a mold section, said cover having an opening, a tube adapted to contain a volatilizable substance extending through said opening and into the space between the electric coil and the cover, a temperature responsive device associated with said tube, connections between the said coil and the temperature responsive device whereby the functioning of the coil is controlled by said temperature responsive device.

13. In combination, a mold adapted for use in vulcanizing rubber articles, an electric heating coil associated with said mold, 'a tube adapted to contain a volatilizable substance associated with said mold, a panel, a pressure responsive device carried by the panel, a conduit connecting the pressure responsive device with the said tube, electric connections between the pressure responsive device and the heating coil for the mold.

In testimony whereof, I hereunto aflix my signature.

WARRE F. CLARK. 

